<!DOCTYPE html>  
<html lang="en">  
<head>  
    <meta charset="UTF-8">  
    <meta name="viewport" content="width=device-width, initial-scale=1.0">  
    <title>Test Page</title>  
</head>  
<body>  
    <button onclick="on()">Click Me</button>  
    <script>  
        function times(f, n) {  
            for (let i = 0; i < n; i++) {  
                f(i);  
            }  
        }  
  
        let a = (index) => {  
            let s = index * (index - 1);  
            console.log(s);  
        };  
  
        function on() {  
            times(a, 4);  
        }  
    </script>  
</body>  
</html>